A. Field of Invention
B. Description of the Related Art
The electrical systems of motor vehicles of all types are becoming increasingly complex. Generally, motor vehicles are provided with one or more wiring harnesses, each of which is a prefabricated bundle of wires having appropriate terminals for interconnection of the appropriate electrical components and systems of the vehicle. Often, a wiring harness, or a portion thereof, must pass through a vehicle bulkhead, including firewalls, acoustical barriers or panels, pressure resistant walls and the like. It has been found most advantageous to utilize multiple terminal connectors to convey a number of electrical terminal connectors through such bulkheads. Additionally, multiple terminal connectors are employed in other situations, both vehicular and non-vehicular, where very large numbers of electrical terminals must be reversibly interconnected.
It is necessary that any multiple terminal electrical connector provide for the rapid, accurate, reversible and reliable interconnection of the appropriate wire pairs. Most multiple terminal connectors comprise a pair of mutable base members, each having one or more of the appropriate terminals retained therein. The base members maintain the terminals in the appropriate orientation and allow for ready connection and disconnection thereof. In most vehicular applications, it is further desirable that the connectors provide for environmentally sealed interconnection of the terminals so as to prevent failures due to moisture or corrosion. It is additionally desirable that the connectors be immune to loosening from vibration or other physical impact.
A connector having a housing adapted to receive a terminal fixture of a wiring harness of an automobile or the like is known. A terminal cavity for the reception of the terminal fixture is formed in the connector housing with the tow ends of the terminal cavity constituting an insertion-side opening through which a terminal fixture is inserted and a connection-side opening with the tip thereof facing the connection-side opening. Afterwards, the terminal fixture within this terminal cavity and the terminal fixture of the mating connector are connected via the connection-side opening. Because such a connector is a general-use part for forming various electrical circuits, i.e. is configured depending on the circuit in which it is employed, terminal fixtures may not be inserted into all of the terminal cavities. That is, some of the terminal cavities may be left vacant. A dummy plug made of rubber and having an outer diameter similar to that of a rubber seal is commonly inserted as a water-resistant measure for such vacant cavities.
Of course, whether a vacant terminal cavity like that described above will be left in the connector can be ascertained in the circuit design stage. Therefore, it is possible to forego this route and instead manufacture specialized connector housings of different specifications by means of differing molds so that excess terminal cavities to be left vacant are not formed. However, such a change in specifications involves a change in the basic structure of the mold. This creates an increase in cost because a completely different mold must be manufactured. This increase in cost is often prohibitive. For reasons such as this, the combination of a general-use connector with dummy plugs has become commonplace in the art.
It is necessary to detect whether or not dummy plugs are already stuffed in empty terminal cavities because there should be no cavities remaining unplugged. However, it is difficult to detect it from the outside due to the fact that each of the dummy plugs is not inserted deeply inside the individual terminal accommodating cavities and are therefore not detectable. In order to complete the detection thereof, there has been provided a device, in which a connector is settled in the main body of the device which is capable of airtightly keeping the interior ambient and provided with pressurized air therein, whereby the existence of stuffed dummy plugs is detected by a change of the inner air pressure. The device as constructed above, is rather costly and requires precision machinery components.
Apart from the above device, a connector terminal detecting tool has been provided. The connector terminal detecting tool can be adapted even for a connector provided with a spacer. The spacer is used in a terminal double-locking operation and is normally disposed at a side surface or back surface of the housing. The tool detects whether or not empty cavities are stuffed by dummy plugs by bringing a contact switch or a detection pin of the connector terminal detecting tool into contact with the dummy plug and checking the result. However, the reliability of this type of detection is not sufficient due to the above difference of the locations of the individual inserted dummy plugs.
The present invention has been made to solve the above-mentioned problems, and accordingly, it is an object of the present invention to provide a dummy plug, whereby it is easily and securely detected whether or not the dummy plugs are stuffed in the terminal cavities presently not in use.
It is well known that dummy plugs have been used to fill unused connector cavities. However, the current dummy plugs are made of rubber and are prone to pressure blowout. Pressure blowout refers to the process where a dummy plug is displaced out of the connector cavity by the action of mating the connectors. Such action compresses the air and, as the pressure rises, eventually causes the air to pop the dummy plug out of the connector cavity. Sometimes this event occurs when another member, such as a connector terminal detecting tool, is inserted the other distal end of the connector cavity.
One known type of dummy plug is disclosed in U.S. Pat. No. 4,993,964 to Trummer. Trummer discloses a plastic plug for use with an electrical connector which precludes the necessity for installation of separate end-seal plugs to effect sealing of any non-used pin contact cavities in the connector. However, the plastic plug used in Trummer does not extend to a latch arm of the connector. Since the plug in Trummer does not extend to the latch arm of the connector, the dummy plug cannot be detected by a pogo pin.
Another known type of dummy plug is disclosed in U.S. Pat. No. 5,551,892 to Endo et al. However, in Endo, the same problem as in the Trummer patent exists. The dummy plug disclosed in Endo is susceptible to the pressure blowout that the current invention is designed to prevent.
Another similar device is disclosed in U.S. Pat. No. 5,562,494 to Fujiwara. Fujiwara discloses a watertight plug comprising a main body having circular ribs on its outside surface and a wire insertion section having a cylindrical section into which a wire is inserted. The Fujiwara invention is used for encasing a wire to create a watertight seal, whereas the current invention is a dummy plug for use in an unused connector cavity.
Another known type of dummy plug is produced by Micro Plastics. However, the Micro Plastics dummy plug is designed for a non-sealed connector system in order to dampen vibration. The Micro Plastics dummy plug, while effective for its designed purpose, does not perform any sealing function.
Difficulties inherent in the related art are therefore overcome in a way that is simple and efficient while providing better and more advantageous results.
In accordance with one aspect of the current invention, a dummy plug for use with an associated wiring harness, the wiring harness having a connector body, two connector cavities, a flange for securing the dummy plug in place, the flange having a top surface and a bottom surface, a latch beam, two latch arms, a first length, a spacer, a perimeter seal, the perimeter seal having two latch arm openings for receiving the latch arms, the dummy plug comprising at least 18 durometer inherently lubricating silicon, a head, multiple ribs, the multiple ribs having a first width, a stem, the stem having a second width, the second width being less than the first width, a female end, the female end having a third width, the third width being less than the first width and greater than the second width, the female end having a base, the base being held in place by the associated bottom surface, and the dummy plug having a second length, the second length being substantially the same as the associated first length, such that the female end is substantially flush with the associated latch arm.
In accordance with still another aspect of the present invention, the dummy plug includes a first end, a second end and a second length, the second length being substantially the same as the first length of the associated wiring harness.
In accordance with another aspect of the present invention, a method for plugging an unused connector cavity includes the steps of providing a dummy plug having a head, a stem, and a female end, providing a wiring harness having at least one connector cavity, and at least one latch arm, and inserting the dummy plug into the unused connector cavity so that the female end is substantially flush with the at least one latch arm.
In accordance with yet another aspect of the current invention, the method further includes the steps of providing a wiring harness having at least one connector cavity, and at least one latch arm, and at least one flange, the flange having a bottom surface and a top surface, and inserting the dummy plug into the unused connector cavity so that the female end is substantially flush with the at least one latch arm and the base of the female end is held in place by the bottom surface of the at least one flange.
In accordance with still another aspect of the present invention, the method further includes placing a spacer on the at least one latch beam, next placing a perimeter seal on the at least one latch beam so that the perimeter seal is substantially flush with the at least one latch arm, and finally placing a pogo pin on the at least one latch arm to verify whether or not the at least one connector cavity is being used.
One advantage of the present invention is that the dummy plug is resistant to pressure blowouts, thereby making the invention functional in the market place.
Another advantage of the present invention is that the dummy plug is flush with the face of the connector, so that a pogo pin can detect whether or not the connector cavity is in use.
Still other benefits and advantages of the invention will become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification.